The invention relates to a dynamic control system. The system includes a control loop with a feedback loop connected from the output of the control loop back to one of the two inputs of a comparator which has a time-variable input connected to its other input. The feedback loop typically includes a measuring or scaling device. The comparator forms a control difference d between a measuring variable m from the measuring device and an input reference w. The control d is connected to a correction device, which produces a corrected output, which in turn drives an adjusting device which produces an output driving a control device, which produces an output X.
A typical device of this type is the so-called phase-locked loop, wherein the comparator is a phase detector having one input connected to the input reference variable and the other input connected to the output of the feedback loop, containing the measuring or scaling device in the form of a frequency divider or a multiplier. The output from the comparator is connected to the correction device which in this case may be a filter. The control device is in this case a voltage-controlled oscillator VCO. The phase locked loop will, at all times, attempt to adjust the phase of the output signal to the phase of the reference input signal in such a way that the phase difference .phi.d always assumes a defined value, especially 0.degree. or 90.degree.. When the reference input signal changes in frequency or phase, the VCO will always seek to adjust to the changed frequency or phase.
A phase-locked loop, however, has certain limitations in regard to stability, acquisition range and acquisition time. These parameters are largely dependent upon the characteristics of the filter.
Control engineering has a multiplicity of different methods available for the purpose of influencing the time delay behavior of dynamic systems in a targeted manner. Certain time-variable quantities of the system are to be shaped to predetermined waveforms and are to be maintained in that form. In principle, this is accomplished by observing the output variables of the system and a change of the input variables of the system on the basis of the information obtained. In the book "Regelungstechnik" (Control Engineering) by Otto Foellinger, Elitera Verlag, Berlin, 1972, basic structures and methods for linear and time-invariant systems with concentrated (lumped) parameters under the influence of deterministic input variables are treated.
Many of the methods described therein can also be applied to non-linear and time variant systems if the latter can be linearized at least in certain regions. If the operating range of the system extends beyond these linearized regions or if there are dead times, distributed parameters or stoichiometric interference variables or is simply an arrangement of a control system which is very complicated, for instance, due to coupling of the variables, it is therefore often not even possible to realize the absolutely necessary requirement as to stability of the control loop with respect to the reference quantities and the interference quantities. Farther-reaching requirements as to the control characteristics, for instance, as to an optimum transient behavior, parameter optimization or control for finite settling time, in particular for optimum control as to speed are therefore not possible, to begin with.
It is accordingly an object of the invention to provide a dynamic control system which overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type and to provide a dynamic control system which has at least one settable system characteristic in a wide operating range.